Believe it or not, this circuit might be the smallest LED flasher ever made! It uses just one transistor, a resistor, and a capacitor to create a blinking LED effect. Imagine achieving this with minimal parts – that's the beauty of this design!
Accidental Discovery (and a History Lesson!)
The discovery of this circuit was a happy accident back in 2006. While trying to miniaturize a motorcycle flasher, the unexpected blinking effect emerged. Later, it was revealed that this phenomenon was already known!
Decades earlier, researchers were exploring the concept of negative resistance in transistors. This tiny flasher actually leverages that principle to create the blinking effect.
We'll delve deeper into negative resistance and its applications in a future article, but for now, let's focus on the fun part – building this simple flasher!
The following diagram proves that a working LED flasher circuit is achievable with just one transistor and a few other components.
Parts List for the proposed single transistor LED flasher circuit
- R1 = 2K7,
- R2 = 100 Ohms,
- T1 = BC 547,
- C1 = 100 uF to 470 uF
- LED = Any Type, any color
The rate of flashing can be adjusted by altering the value of either R1 or C1, or both simultaneously. However, the supply voltage should not be less than 9V, as it may cause the circuit to malfunction.
Circuit Diagram
Connecting an External Transistor to Handle Higher Loads
PCB Design
